First report of rust caused by aecial stage of Puccinia klugkistiana on Ligustrum japonicum in Korea.
Ligustrum japonicum (Oleraceae), called Japanese privet or waxleaf privet, is native to Japan and southern Korea. Owing to its attractive evergreen foliage, it is widely cultivated in other regions with warm temperate climates. This shrub is also naturalized in California and in the southeastern USA from Texas to Virginia. In June 2016, hundreds of L. japonicum shrubs were found affected by a rust at a disease incidence of 50% in a public garden in Daegu, Korea. Similar symptoms with typical rust pustules on this plant species were also found in Jinju, Korea. Examination of an affected plant revealed that orange-yellow rust pustules were formed on the lower leaf surface with corresponding yellowish to chlorotic lesions on the upper surface. Based on morphological characteristics, molecular data (internal transcribed spacer and large subunit regions of rRNA gene) and pathogenicity tests, the causal agent was identified as Puccinia klugkistiana. The aecial stage of P. klugkistiana has been reported on eight species/varieties of Ligustrum from East Asia including China, Japan, and Korea. In Korea, L. ibota and L. obtusifolium have been recorded as host plants of the aecial stage of P. klugkistiana. This is thought to be the first report of the aecial stage of P. klugkistiana on L. japonicum in Korea. Rust infection caused necrotic lesions, greatly detracting from the beauty of the glossy leaves.